Brushless permanent-magnet (PM) motors and generators are commonly used small devices and/or devices that operate at high-speed. They are less commonly utilized in slow speed applications due to the assembly difficulties associated with maneuvering a large magnet and because of the difficulty of eliminating enough cogging torque for slow-speed applications.
An example of a slow-speed application that has rarely used a brushless PM generator is wind power. Slow-speed operation often utilizes a gearbox to turn the generator at a higher speed. In addition to efficiency losses, the gearbox necessitates a larger structure to support the additional weight of the gearbox/generator assembly. Thus, there is a need in the art for a generator that includes a permanent magnet, and reduces cogging torque for use in slow-speed applications.